Burglar-alarm.



' UNITED STATES PATENT "Centola CLARENCE E. SPENCER AND JOHN T. PETHICK, OF CARBCNDALE,

' PENNSYLVANIA.

BURGLAR-ALARIVI.

SPECIFICATION fo1ming part of Letters Patent No. 633,396, dated September 19, 1899. Application filed June 13, 1899. Serial No. 720,357. (No model.)

T0 all whom t may concern:

Be it known that we,CLARENcE ESPENCER and JOHN T. PETHICK, citizens of the United States of America, residing at Carbondale, in the county of Lackawanna and State of'Pennsylvania, have invented certain new and useful Improvements in Burglar Alarins, of which the following is a specification.

Our invention relates to an improvement in burglar-alarms; and the object is to provide a sim ple, inexpensive, and effectual article of manufacture for application to winvdows and doors for givingan alarm to the occupants of the buildings whereon they are applied when an attempt is made to burglarize them or a forced entrance of any kind is attempted.

With tho foregoing object in view our invention consists in certain novel features of construction and combinations of parts as will be more fully described hereinafter, and particularly pointed out in the claim.

In the accompanying drawings, Figure 1 is a view showing the device applied in position on a window-casing, and Figs. 2 and 3 are detached views showing the burglar-alarm from different points of view.

Arepresents the frame of the device, preferably made of cast metal in the general shape outlined in the drawings-that is to say, substantially flat on its inner face where it rests upon the window-casing, doorframe, or oor, as the case may be, terminating in lugs or ears l 1 at its opposite ends,and having holes 2 2 therein to receive a screw or other attaching means for holding it in place, and enlarged at 3 with a hole 4, formed tra-nsversely therein to receive a percussion-cap. On the opposite side from this enlargement 3 an arm 5 is formed. This arm is preferably split, as at 6, and in the inner face of the split portion the inwardly-opening bearings or sockets 7 7 are formed.

Bis a hammer provided with trunnions S S, which fit and turn in the open bearings or sockets 7 7'. Adjacent to the trunnions and at the inner end of the hammer the two converging cam-surfaces 9 and 10 are formed, they coming together at a moderately sharp angle 11.

A small plate-spring 12 is secured in a slit or slot in the frame with one end bearing against one or the other of the cam-surfaces of the hammer. The action of this spring may be said to be threefold: First, it is u tilized by its outward pressure to retain the trunnions of the hammer in the bearings or sockets 7 7; second, it acts upon the outer cam-surface 9 when the hammer is raised or set to retain it in its set position, and, third, it serves to impart a quick movement to the hammer when the spring has passed the dead-center point upon the hammer, thus imparting an impact upon the cap and causing it to explode with a sharp report.

The hammer has an outwardly-turned ear 13 at its rear end, by which it is grasped by the thumb or a finger to pull it back and set it. When applied to a window-casing, the deviceis so placed that the hammer extends into the path of the window-sash, so that the window upon being moved against itforces the hammer to a point where the dead-center is crossed by the spring, and the hammer dies against the cap with sufficient force to eX- plode it.

It is obvious that the device is very simple and capable of being manufactured and placed upon the market at a small initial cost, as it consists of a few number of parts which may be easily made and pnt together. The application to a window or door .requires no special skill, as any one can attach it by the use of a hammer or screw-driver. Furthermore, in operation it is most effective.

Slight changes might be resorted to in the form and arrangement of the several parts described-such as, for instance, the general shape of the parts, the particular variety of spring, and the bearings for the hammerwithout departing from the spirit and scope of our invention, -and hence we do not Wish to limit lourselves to the exact construction herein shown and described; but,

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is"

The combination with a main frame having au enlargement therein to form a seat for a percussion-cap, an arm projecting from the frame and having inwardly-opening bearings or sockets formed therein, of a removable hannner provided with lrunnions which turn in these bearings or sockets, the hammer provided Wibh converging cams and a spring conneeted with the frame and housed and guarded bythe main portion and the arm and normally bearing upon one or the other of the oonvergingcams, said spring having the three functions of retaining the trunnions in their i bearings or sockets, looking the hammer in its raised position and imparting a sudden xo impact of the hammer upon the cap when it, 1s released from its looked position.

CLARENCE E. SPENCER. JOHN T. PETHICK.

In presence of E. A. WHEELER, R.- S. RETTEW. 

